Hello,
If you put in model number shu5004 into the model number search on Partselect.com it will give your a brake down of your dishwasher. I would start with the easy things first such as making sure the dishwasher is using hot water which is critical to clean dishes. Also, the water level needs to be about even with the heating element at the bottom of the tub. Also, check the spray arm for cracks or blockage. This is a start. As long as your water level is correct and your water is hot and, your pump is spraying the water freely, your dishes should come out clean.
JP
February 2008